Polyvinyl chloride fiber, process for producing the same, and use thereof

ABSTRACT

Polyvinyl chloride fibers obtainable by molding a resin composition containing 100 parts by weight of a vinyl chloride resin, from 3 to 20 parts by weight of a compatible chlorinated vinyl chloride resin, from 10 to 30 parts by weight of a heat resistant chlorinated vinyl chloride resin, and from 0.1 to 10 parts by weight of a heat stabilizer into a fibrous form, the compatible chlorinated vinyl chloride resin having a chlorine content of from 57 to 64% by weight and an average degree of polymerization of from 450 to 800; and the heat resistant chlorinated vinyl chloride resin having a chlorine content of from 65 to 71% by weight and an average degree of polymerization of from 450 to 1,100, to a process of producing the same and to applications thereof.

FIELD OF THE INVENTION

The present invention relates to polyvinyl chloride fibers, especiallypolyvinyl chloride fibers which are small in heat shrinkage even in anatmosphere of 100° C. or higher while keeping conventional spinningperformance, to a process for producing the same and to applicationsthereof.

BACKGROUND ART

Vinyl chloride resins are utilized for various applications as a typicalgeneral-purpose plastic because they are excellent in transparency, fireretardancy and chemical resistance and inexpensive. Of these, polyvinylchloride fibers are closed to natural hairs with respect to strength,ductility, and so on and therefore, are frequently used as fibers forartificial hairs for the hair. Polyvinyl chloride fibers themselves areshrunk beyond the need due to heat in secondary processing. As means forsolving this, a process of producing polyvinyl chloride fibers made of acomposition containing a vinyl chloride resin and a heat resistantchlorinated vinyl chloride resin is disclosed (for example, PatentDocument 1).

The polyvinyl chloride fibers of this means are one in which a componentof one side is dispersed as an island component in the other componentwithin the fibers, and the fibers are crimped by heating.

However, in the polyvinyl chloride fibers of the foregoing means, ifheat of 100° C. or higher is applied for the purpose of secondaryprocessing of the fibers, the fibers are heat shrunk beyond the need sothat the processing characteristics become inferior.

For the sake of adjusting the crimping properties of fibers, a method inwhich the blending amount of a chlorinated vinyl chloride resin in thecomposition is increased, thereby lowering heat shrinkage of the resincomposition itself may be considered. Originally, a vinyl chloride resinand a chlorinated vinyl chloride resin are poor in compatibility. Thus,if the blending amount of the chlorinated vinyl chloride resin is merelyincreased, phase separation takes place in melt-spinning fibers so thatthe spinning performance are deteriorated, and therefore, such is notpreferable.

For the purpose of enhancing the compatibility between a vinyl chlorideresin and a chlorinated vinyl chloride resin, a method of adding anethylene-vinyl acetate/vinyl chloride graft polymer resin resulting fromgraft polymerization of vinyl chloride on an ethylene-vinyl acetatecopolymer is disclosed (for example, Patent Document 2).

However, since the heat shrinkage of the ethylene-vinyl acetate/vinylchloride graft polymer resin itself is equivalent to that of the vinylchloride resin, even if the compatibility between the vinyl chlorideresin and the chlorinated vinyl chloride resin is enhanced, the heatshrinkage of the resin composition itself is increased, and therefore,such is not preferable. While it is required to select a resin havingitself heat resistance to some extent while enhancing the compatibilitybetween the vinyl chloride resin and the chlorinated vinyl chlorideresin, it has not reached selection of a satisfactory resin yet.

[Patent Document 1]

JP-B-60-18323

[Patent Document 2]

JP-A-10-102317

DISCLOSURE OF THE INVENTION

An object of the invention is to provide polyvinyl chloride fibers whichenhance compatibility between a vinyl chloride resin and a chlorinatedvinyl chloride resin and are small in heat shrinkage even in anatmosphere of 100° C. or higher while keeping spinning performance atthe time of melt-spinning, a process of producing the same, andapplications thereof.

In view of the foregoing, the present inventor made extensive andintensive investigations regarding a formulation of a resin composition.As a result, it has been found that by formulating a specific resincomposition, the foregoing problems can be solved, leading toaccomplishment of the invention. The invention has the followingconstructions.

(1) Polyvinyl chloride fibers obtainable by molding a resin compositioncontaining 100 parts by weight of a vinyl chloride resin, from 3 to 20parts by weight of a compatible chlorinated vinyl chloride resin, from10 to 30 parts by weight of a heat resistant chlorinated vinyl chlorideresin, and from 0.1 to 10 parts by weight of a heat stabilizer into afibrous form,

wherein the compatible chlorinated vinyl chloride resin has a chlorinecontent of from 57 to 64% by weight and an average degree ofpolymerization of from 450 to 800, and the heat resistant chlorinatedvinyl chloride resin has a chlorine content of from 65 to 71% by weightand an average degree of polymerization of from 450 to 1,100.

(2) The polyvinyl chloride fibers according to the above (1), whereinthe compatible chlorinated vinyl chloride resin has a fluidity of 0.05cc/sec or more and not more than 0.2 cc/sec, and the heat resistantchlorinated vinyl chloride resin has a fluidity of 0.005 cc/sec or moreand less than 0.05 cc/sec.

(3) The polyvinyl chloride fibers according to the above (1) or (2),wherein the heat stabilizer is one kind or a mixture of two or morekinds selected from hydrotalcite compounds, calcium-zinc basedcompounds, epoxy compounds, organic phosphite compounds, andβ-diketones.

(4) A process for producing polyvinyl chloride fibers, comprisingforming a resin composition containing 100 parts by weight of a vinylchloride resin, from 3 to 20 parts by weight of a compatible chlorinatedvinyl chloride resin, from 10 to 30 parts by weight of a heat resistantchlorinated vinyl chloride resin, and from 0.1 to 10 parts by weight ofa heat stabilizer into a fibrous form,

wherein the compatible chlorinated vinyl chloride resin has a chlorinecontent of from 57 to 64% by weight and an average degree ofpolymerization of from 450 to 800, the heat resistant chlorinated vinylchloride resin has a chlorine content of from 65 to 71% by weight and anaverage degree of polymerization of from 450 to 1,100, and

wherein the measure for forming into a fibrous form being melt-spinning.

(5) The process of producing polyvinyl chloride fibers according to theabove (4), wherein the compatible chlorinated vinyl chloride resin has afluidity of 0.05 cc/sec or more and not more than 0.2 cc/sec, and theheat resistant chlorinated vinyl chloride resin has a fluidity of 0.005cc/sec or more and less than 0.05 cc/sec.

(6) The process of producing polyvinyl chloride fibers according to theabove (4) or (5), wherein the heat stabilizer is one kind or a mixtureof two or more kinds selected from hydrotalcite compounds, calcium-zincbased compounds, epoxy compounds, organic phosphite compounds, andβ-diketones.

(7) A resin composition for polyvinyl chloride fibers, which comprises100 parts by weight of a vinyl chloride resin, from 3 to 20 parts byweight of a compatible chlorinated vinyl chloride resin, from 10 to 30parts by weight of a heat resistant chlorinated vinyl chloride resin,and from 0.1 to 10 parts by weight of a heat stabilizer into a fibrousform,

wherein the compatible chlorinated vinyl chloride resin has a chlorinecontent of from 57 to 64% by weight and an average degree ofpolymerization of from 450 to 800, and the heat resistant chlorinatedvinyl chloride resin has a chlorine content of from 65 to 71% by weightand an average degree of polymerization of from 450 to 1,100.

(8) The resin composition for polyvinyl chloride fibers according to theabove (7), wherein the compatible chlorinated vinyl chloride resin has afluidity of 0.05 cc/sec or more and not more than 0.2 cc/sec, and theheat resistant chlorinated vinyl chloride resin has a fluidity of 0.005cc/sec or more and less than 0.05 cc/sec.

(9) The resin composition for polyvinyl chloride fibers according to theabove (7) or (8), wherein the heat stabilizer is one kind or a mixtureof two or more kinds selected from hydrotalcite compounds, calcium-zincbased compounds, epoxy compounds, organic phosphite compounds, andβ-diketones.

(10) Artificial hairs formed of the polyvinyl chloride fibers accordingto the above (1) or (3).

Since the polyvinyl chloride fibers of the invention are small in heatshrinkage even in an atmosphere of 100° C. or higher while keepingspinning performance at the time of melt-spinning, they can be suitablyused as fibers for artificial hairs for the hair.

According to the process of producing polyvinyl chloride fibers of theinvention, polyvinyl chloride fibers capable of solving the foregoingproblems can be suitably produced.

According to the resin composition of the invention, by employing theforegoing specific construction, fibers for artificial hairs for thehair can be produced because of small heat shrinkage even in anatmosphere of 100° C. or higher while keeping spinning performance atthe time of melt-spinning.

The artificial hairs of the invention are small in heat shrinkage evenin an atmosphere of 100° C. or higher.

According to the invention of this application, by mixing a vinylchloride resin with a compatible chlorinated vinyl chloride resin and aheat resistant chlorinated vinyl chloride resin each having specificchlorine content, average degree of polymerization and fluidity in asuitable blending ratio, polyvinyl chloride fibers capable of loweringheat shrinkage to proper extent without impairing spinning performance,a process for producing the same and applications thereof have beenfound.

According to the present invention, by selecting a heat stabilizer amongspecific combinations, a synergistic effect between the heat stabilizerand the compatible chlorinated vinyl chloride resin is obtained, and itcan be designed to enhance spinning performance of the resin compositionand to prevent heat decomposition.

BEST MODE FOR CARRYING OUT THE INVENTION

As the vinyl chloride resin to be used in the invention, known resinswhich are generally used as polyvinyl chloride fibers can be employed,and specific examples thereof include a vinyl chloride homopolymer,copolymers of vinyl chloride with ethylene, propylene, alkyl vinylethers, vinylidene chloride, vinyl acetate, acrylic esters, maleicesters, etc., and mixtures thereof. However, the degree ofpolymerization is preferably from 600 to 1,300. When the degree ofpolymerization is less than 600, the melt viscosity is lowered so thatthe resulting fibers may possibly be likely heat shrunk, and when itexceeds 1,300, the molding temperature rises with an increase of themelt viscosity so that the fibers may possibly cause coloration.

The compatible chlorinated vinyl chloride resin and the heat resistantchlorinated vinyl chloride resin which are used in the invention areones obtained by chlorinating a vinyl chloride resin.

The chlorine content of the compatible chlorinated vinyl chloride resinis from 57 to 64% by weight (hereinafter, the chlorine content will beexpressed merely by “%”). Within this range, the compatible chlorinatedvinyl chloride resin has compatibility with any of the vinyl chlorideresin and the heat resistant chlorinated vinyl chloride resin asdescribed later.

When the chlorine content of the compatible chlorinated vinyl chlorideresin is less than 57%, the compatibility with the heat resistant vinylchloride resin tends to become worse, and when it exceeds 64%, thecompatibility with the vinyl chloride resin tends to become worse.

The average degree of polymerization of the compatible chlorinated vinylchloride resin is from 450 to 800. When the average degree ofpolymerization is less than 450, an effect for lowering the heatshrinkage of the polyvinyl chloride fibers is not obtained, and when itexceeds 800, the spinning performance become worse.

The blending amount of the compatible chlorinated vinyl chloride resinis from 3 to 20 parts by weight, preferably from 3 to 15 parts byweight, and more preferably from 3 to 10 parts by weight, based on 100parts by weight of the vinyl chloride resin. When the blending amount isless than 3 parts by weight, an effect as a compatibilizing agent cannotbe sufficiently revealed so that the spinning performance become worse;and even when the compatible chlorinated vinyl chloride resin is blendedin an amount exceeding 20 parts by weight, the effect reaches the peak,and the heat shrinkage of the polyvinyl chloride fibers tends to becomelarge.

The fluidity of the compatible chlorinated vinyl chloride resin is 0.05cc/sec or more and not more than 0.2 cc/sec. When the fluidity is 0.05cc/sec or more, the compatibility with the vinyl chloride resin becomesgood, and hence, such is preferable; and when it is not more than 0.2cc/sec, the compatibility with the heat resistant chlorinated vinylchloride resin becomes good, and hence, such is preferable.

The value of the fluidity is one obtained by measuring a compositioncontaining 2.0 parts by weight of a tin based stabilizer, 0.7 parts byweight of a higher fatty acid, 2.3 parts by weight of an ester wax, and10 parts by weight of a methyl methacrylate/butadiene/styrene copolymerbased on 100 parts by weight of the chlorinated vinyl chloride resinunder a condition having a temperature of 190° C., a load of 100 kg/cm²and a die dimension of 1φ×1 mm using a Koka flow tester, and all of thefluidities in this application are ones measured by this method.

The heat resistant chlorinated vinyl chloride resin is an essentialcomponent for the purpose of lowering the heat shrinkage. The chlorinecontent of this resin is from 65 to 71%. When the chlorine content isless than 65%, an effect for lowering the heat shrinkage is notobtained, and when it exceeds 71%, the spinning performance tend tobecome worse.

The average degree of polymerization of the heat resistant chlorinatedvinyl chloride resin is from 450 to 1,100. When the average degree ofpolymerization is less than 450, an effect for lowering the heatshrinkage is not obtained, and when it exceeds 1,100, the spinningperformance tend to become worse.

The blending amount of the heat resistant chlorinated vinyl chlorideresin is from 10 to 30 parts by weight, preferably from 10 to 20 partsby weight, and more preferably from 10 to 15 parts by weight, based on100 parts by weight of the vinyl chloride resin. When the blendingamount is less than 10 parts by weight, an effect for lowering the heatshrinkage is not obtained; and when the heat resistant chlorinated vinylchloride resin is blended in an amount exceeding 30 parts by weight, thespinning performance tend to become worse.

The fluidity of the heat resistant chlorinated vinyl chloride resin is0.005 cc/sec or more and less than 0.05 cc/sec. When the fluidity is0.005 cc/sec or more, the spinning performance become good, and hence,such is preferable; and when it is less than 0.05 cc/sec, an effect forlowering the heat shrinkage is obtained, and hence, such is preferable.

In the invention, the heat stabilizer is necessary for enhancing thespinning performance of the resin composition and inhibiting heatdecomposition of the resin composition itself from occurrence inmelt-spinning the resin composition due to a synergistic effect with thecompatible chlorinated vinyl chloride resin to be blended in the resincomposition.

The blending amount of the heat stabilizer is from 0.1 to 10 parts byweight, preferably from 3 to 10 parts by weight, and more preferablyfrom 5 to 10 parts by weight, based on 100 parts by weight of the vinylchloride resin. When the blending amount is less than 0.1 parts byweight, an effect for preventing the heat decomposition at the time ofmelt-spinning is not obtained; and when the heat stabilizer is blendedin an amount exceeding 10 parts by weight, a block of the resin isformed in the vicinity of an outlet of a mold so that there is atendency that spinning cannot be stably carried out.

As the heat stabilizer, known ones such as hydrotalcite based,calcium-zinc based, epoxy based, organic phosphite based, β-diketonebased, zeolite based, mercapto tin based, tin maleate based, tin lauratebased and barium-zinc based stabilizers can be used. Of these, one kindor a mixture of two or more kinds of hydrotalcite based, calcium-zincbased, epoxy based, organic phosphite based and β-diketone basedstabilizers are especially preferable because long-term stability at thetime of spinning and a synergistic effect with the compatiblechlorinated vinyl chloride resin are more likely obtained.

So far as the effects of the invention are not hindered, conventionallyknown additives which are used in resin compositions may be blended inthe resin composition of the invention according to the purpose.Examples of the additives include a lubricant, a resin for modification,a processing auxiliary, a reinforcing agent, an ultraviolet lightabsorber, an antioxidant, an antistatic agent, a filler, a fireretardant, a pigment, an initial color improver, a conductivityimparting agent, a surface treating agent, a delusterant, a lightstabilizer, and a flavor.

With respect to the size of a single thread of the polyvinyl chloridefiber, a size of from 20 to 100 deniers is suitable for the artificialhairs because a nature-like effect is revealed, and a size of from 50 to80 deniers is more suitable in view of the touch and texture.

The cross-sectional shape of the polyvinyl chloride fibers forartificial hairs of the invention may be any shape, for example, acircular shape, an elliptic shape, a spectacle shape (a shape whereintwo circles are connected via a rectangle), a star shape, a C-shape, anH-shape, a T-shape, a Y-shape, a cross shape, a triangular shape, aheart shape, a cocoon shape (a shape wherein two circles are partlyoverlaid), or a hollow body thereof. Also, fibers having variouscross-sectional shapes can be properly combined and used.

With respect to the production process of polyvinyl chloride fibers, thepolyvinyl chloride fibers are obtained by mixing the resin compositionof this application using a conventionally known mixing machine (forexample, a Henschel mixer and a ribbon blender) and melt-spinning themixture using a conventionally known metal extruder (for example, asingle screw extruder, a counter-rotating two screw extruder, and aconical twin-screw extruder), followed by a stretching treatment stepand a thermal relaxation treatment step.

Examples of the artificial hairs according to the invention include onesfor decorating the hair, for example, wigs, hairpieces, braids,extension hairs, and accessory hairs, and doll hairs.

EXAMPLES

The invention will be more specifically described below with referenceto the Examples and Comparative Examples, but it should not be construedthat the invention is limited to these Examples so far as they do notexceed the gist of the invention.

(Specializing Method of Chlorinated Vinyl Chloride Resin)

<Fluidity>

The fluidity is one obtained by measuring a composition containing 2.0parts by weight of a tin based stabilizer, 0.7 parts by weight of ahigher fatty acid, 2.3 parts by weight of an ester wax, and 10 parts byweight of a methyl methacrylate/butadiene/styrene copolymer based on 100parts by weight of the chlorinated vinyl chloride resin under acondition having a temperature of 190° C., a load of 100 kg/cm² and adie dimension of 1φ×1 mm using a Koka flow tester.

(Evaluation Method of Characteristics)

1. Heat Shrinkage:

The heat shrinkage expresses a degree of shrinkage generated in heattreating a specimen. In testing the heat shrinkage, a specimen adjustedso as to have a length of 100 mm is heat treated in a gear oven of 100°C. for 15 minutes, a ratio of the length of the specimen before andafter the heat treatment is measured, and a ratio of heat shrinkage isdetermined from an average value of ten specimens. The case where theratio of heat shrinkage is less than 7% was evaluated as “⊚”; the casewhere it is 7% or more and less than 10% was evaluated as “◯”; and thecase where it is 10% or more was evaluated as “×”. In products, while aratio of heat shrinkage in products is required to be less than 10%, itis more preferable that the ratio of heat shrinkage is less than 7%.

2. Spinning Performance:

The spinning performance express molding performance in melt-spinning aresin composition. In testing the spinning performance, when 120 threadsof fibrous bodies are extrusion molded simultaneously from a spinningmold, the number of occurrence of thread breakage (a phenomenon whereinseveral threads of fibrous bodies are broken during the melt extrusion)is measured.

The case where the number of occurrence of thread breakage during themeasurement is 0 was evaluated as “502 ”; the case where it is 1 wasevaluated as “◯”; and the case where it is 2 or more was evaluated as“×”. An appropriate condition in the production is not more than 1.Incidentally, the measurement time was 30 minutes, and the number ofmeasurement was 3. TABLE 1 Example 1 2 3 4 Blending: Vinyl chlorideresin Blending amount (parts by weight) 100 100 100 100 CompatibleBlending amount (parts by weight) 5 15 7 7 chlorinated vinyl Chlorinecontent (%) 63 61 61 62 chloride resin Degree of polymerization 800 600600 700 Fluidity (cc/sec) 0.03 0.12 0.12 0.06 Heat resistant Blendingamount (parts by weight) 11 15 12 12 chlorinated vinyl Chlorine content(%) 67 66 67 69 chloride resin Degree of polymerization 700 500 700 600Fluidity (cc/sec) 0.02 0.07 0.02 0.01 Heat stabilizer Blending amount(parts by weight) 0.5 9 8 8 Characteristics: Heat shrinkage ◯ ◯ ⊚ ⊚Spinning performance ◯ ⊚ ⊚ ⊚

TABLE 2 Comparative Example 1 2 3 4 5 6 7 Blending: Vinyl chloride resinBlending amount (parts by weight) 100 100 100 100 100 100 100 CompatibleBlending amount (parts by weight) 2 22 7 7 7 7 7 chlorinated vinylChlorine content (%) 61 61 56 65 63 61 61 chloride resin Degree ofpolymerization 600 600 800 600 400 850 600 Fluidity (cc/sec) 0.12 0.120.15 0.06 0.25 0.04 0.12 Heat resistant Blending amount (parts byweight) 12 12 12 12 12 12 8 chlorinated vinyl Chlorine content (%) 67 6767 67 67 67 67 chloride resin Degree of polymerization 700 700 700 700700 700 700 Fluidity (cc/sec) 0.02 0.02 0.02 0.02 0.02 0.02 0.02 Heatstabilizer Blending amount (parts by weight) 8 8 8 8 8 8 8Characteristics: Heat shrinkage ⊚ X X ⊚ X ⊚ X Spinning performance X ⊚ ⊚X ⊚ X ⊚ Comparative Example 8 9 10 11 12 13 14 Blending: Vinyl chlorideresin Blending amount (parts by weight) 100 100 100 100 100 100 100Compatible Blending amount (parts by weight) 7 7 7 7 7 7 7 chlorinatedvinyl Chlorine content (%) 61 61 61 61 61 61 61 chloride resin Degree ofpolymerization 600 600 600 600 600 600 600 Fluidity (cc/sec) 0.12 0.120.12 0.12 0.12 0.12 0.12 Heat resistant Blending amount (parts byweight) 33 12 12 12 12 12 12 chlorinated vinyl Chlorine content (%) 6764 73 69 66 67 67 chloride resin Degree of polymerization 700 700 500400 1150 700 700 Fluidity (cc/sec) 0.02 0.04 0.003 0.03 0.01 0.02 0.02Heat stabilizer Blending amount (parts by weight) 8 8 8 8 8 0.05 12Characteristics: Heat shrinkage ⊚ X ⊚ X ⊚ X X Spinning performance X ⊚ X⊚ X X X

Example 1

Polyvinyl chloride fibers to be used in Example 1 are ones obtained bymelt-spinning a resin composition of a blend of 100 parts by weight of avinyl chloride resin (TH-1000, manufactured by Taiyo Vinyl Corp.), 5parts by weight of a compatible chlorinated vinyl chloride resin (acustom-made, manufactured by Sekisui Chemical Co., Ltd.), 11 parts byweight of a heat resistant chlorinated vinyl chloride resin

(a custom-made, manufactured by Sekisui Chemical Co., Ltd.), and 0.5parts by weight of a heat stabilizer (CP-234A, manufactured by NissanChemical Industries, Ltd.) by a melt extruder, followed by a stretchingstep and a thermal relaxation treatment step to mold in an averagefineness of 60 deniers. The chlorine content, degree of polymerizationand fluidity of each of the used compatible chlorinated vinyl chlorideresin and heat resistant chlorinated vinyl chloride resin were shown inTable 1.

The melt-spinning of the polyvinyl chloride fibers was carried out byextrusion molding the foregoing composition at an extrusion rate of 10kg/hr so as to have an average fineness of 180 deniers from a spinningmold having a nozzle cross-sectional area of 0.06 mm², the number ofpores of 120 and a mold temperature of 175° C. The stretching treatmentwas carried out by stretching the fibers resulting from melt-spinning toa degree of 300% in an air atmosphere of 105 ° C.; and the thermalrelaxation treatment was carried out by heat treating the stretchedfibers in an air atmosphere of 110 ° C. until the whole length of fiberbecame 75% of the length before the treatment.

Examples 2 to 4

Polyvinyl chloride fibers were obtained in the same manner as in Example1, except for changing the blending amount, chlorine content, degree ofpolymerization and fluidity of each of the used resins and the blendingamount of the heat stabilizer to the values shown in Table 1, and thenevaluated in the same manner.

Comparative Examples 1 to 14

Polyvinyl chloride fibers were obtained in the same manner as in Example1, except for changing the blending amount, chlorine content, degree ofpolymerization and fluidity of each of the used resins and the blendingamount of the heat stabilizer to the values shown in Table 2, and thenevaluated in the same manner.

The evaluation results of the respective Examples and ComparativeExamples were summarized and shown in Tables 1 and 2. The polyvinylchloride fibers of the respective Examples were in a usable level (◯ ormore) with respect to all of the spinning performance and heat shrinkproperties; and those of Examples 3 and 4 included many good levels (⊚)among the respective evaluation items. The polyvinyl chloride fibers ofComparative Examples 1 to 14 were problematic with respect to themelt-spinning properties or heat shrink properties.

While the invention has been described in detail and with reference tospecific embodiments thereof, it will be apparent to one skilled in theart that various changes and modifications can be made therein withoutdeparting from the spirit and scope thereof.

This application is based on a Japanese patent application filed Apr. 4,2003 (Japanese Patent Application No. 2003-101663) and a Japanese patentapplication filed May 13, 2002 (Japanese Patent Application No.2003-134604), the contents of which are incorporated therein and madehereof by reference.

INDUSTRIAL APPLICABILITY

The invention is concerned with polyvinyl chloride fibers obtained bymolding a resin composition containing a vinyl chloride resin andspecific chlorinated vinyl chloride resins into a fibrous form, aprocess of producing the same and applications thereof. According to theinvention, polyvinyl chloride fibers which are small in heat shrinkproperties even in an atmosphere of 100° C. or higher in secondaryprocessing for the purpose of using for artificial hairs, etc., aprocess of producing the same and applications thereof can be obtained.

1. Polyvinyl chloride fibers obtainable by molding a resin compositioncontaining 100 parts by weight of a vinyl chloride resin, from 3 to 20parts by weight of a compatible chlorinated vinyl chloride resin, from10 to 30 parts by weight of a heat resistant chlorinated vinyl chlorideresin, and from 0.1 to 10 parts by weight of a heat stabilizer into afibrous form, wherein the compatible chlorinated vinyl chloride resinhas a chlorine content of from 57 to 64% by weight and an average degreeof polymerization of from 450 to 800, and the heat resistant chlorinatedvinyl chloride resin has a chlorine content of from 65 to 71% by weightand an average degree of polymerization of from 450 to 1,100.
 2. Thepolyvinyl chloride fibers according to claim 1, wherein the compatiblechlorinated vinyl chloride resin has a fluidity of 0.05 cc/sec or moreand not more than 0.2 cc/sec, and the heat resistant chlorinated vinylchloride resin has a fluidity of 0.005 cc/sec or more and less than 0.05cc/sec.
 3. The polyvinyl chloride fibers according to claim 1, whereinthe heat stabilizer is one kind or a mixture of two or more kindsselected from hydrotalcite compounds, calcium-zinc based compounds,epoxy compounds, organic phosphite compounds, and β-diketones.
 4. Aprocess for producing polyvinyl chloride fibers, comprising forming aresin composition containing 100 parts by weight of a vinyl chlorideresin, from 3 to 20 parts by weight of a compatible chlorinated vinylchloride resin, from 10 to 30 parts by weight of a heat resistantchlorinated vinyl chloride resin, and from 0.1 to 10 parts by weight ofa heat stabilizer into a fibrous form, wherein the compatiblechlorinated vinyl chloride resin has a chlorine content of from 57 to64% by weight and an average degree of polymerization of from 450 to800, the heat resistant chlorinated vinyl chloride resin has a chlorinecontent of from 65 to 71% by weight and an average degree ofpolymerization of from 450 to 1,100, and wherein the measure for forminginto a fibrous form being melt-spinning.
 5. The process of producingpolyvinyl chloride fibers according to claim 4, wherein the compatiblechlorinated vinyl chloride resin has a fluidity of 0.05 cc/sec or moreand not more than 0.2 cc/sec, and the heat resistant chlorinated vinylchloride resin has a fluidity of 0.005 cc/sec or more and less than 0.05cc/sec.
 6. The process of producing polyvinyl chloride fibers accordingto claim 4, wherein the heat stabilizer is one kind or a mixture of twoor more kinds selected from hydrotalcite compounds, calcium-zinc basedcompounds, epoxy compounds, organic phosphite compounds, andβ-diketones.
 7. A resin composition for polyvinyl chloride fibers, whichcomprises 100 parts by weight of a vinyl chloride resin, from 3 to 20parts by weight of a compatible chlorinated vinyl chloride resin, from10 to 30 parts by weight of a heat resistant chlorinated vinyl chlorideresin, and from 0.1 to 10 parts by weight of a heat stabilizer into afibrous form, wherein the compatible chlorinated vinyl chloride resinhas a chlorine content of from 57 to 64% by weight and an average degreeof polymerization of from 450 to 800, and the heat resistant chlorinatedvinyl chloride resin has a chlorine content of from 65 to 71% by weightand an average degree of polymerization of from 450 to 1,100.
 8. Theresin composition for polyvinyl chloride fibers according to claim 7,wherein the compatible chlorinated vinyl chloride resin has a fluidityof 0.05 cc/sec or more and not more than 0.2 cc/sec, and the heatresistant chlorinated vinyl chloride resin has a fluidity of 0.005cc/sec or more and less than 0.05 cc/sec.
 9. The resin composition forpolyvinyl chloride fibers according to claim 7, wherein the heatstabilizer is one kind or a mixture of two or more kinds selected fromhydrotalcite compounds, calcium-zinc based compounds, epoxy compounds,organic phosphite compounds, and β-diketones.
 10. Artificial hairsformed of the polyvinyl chloride fibers according to claim
 1. 11. Thepolyvinyl chloride fibers according to claim 2, wherein the heatstabilizer is one kind or a mixture of two or more kinds selected fromhydrotalcite compounds, calcium-zinc based compounds, epoxy compounds,organic phosphite compounds, and β-diketones.
 12. The process ofproducing polyvinyl chloride fibers according to claim 5, wherein theheat stabilizer is one kind or a mixture of two or more kinds selectedfrom hydrotalcite compounds, calcium-zinc based compounds, epoxycompounds, organic phosphite compounds, and β-diketones.
 13. The resincomposition for polyvinyl chloride fibers according to claim 8, whereinthe heat stabilizer is one kind or a mixture of two or more kindsselected from hydrotalcite compounds, calcium-zinc based compounds,epoxy compounds, organic phosphite compounds, and β-diketones. 14.Artificial hairs formed of the polyvinyl chloride fibers according toclaim 3.